Patio & French Door Locks

Most uPVC patio sliders and French doors in Slough use a multipoint locking system: when you lift the handle and turn the key, a central gearbox drives a series of locking points — hooks, rollers, hook bolts and mushroom cams — into keeps set into the frame. This means you are not relying on a single latch but on four, five or more engagement points along the edge of the door. It is a robust system in principle, but it has a central weakness: every moving part passes through or connects to that one gearbox, and if the gearbox wears out, the whole mechanism fails. The euro cylinder that the key turns is a separate component and also vulnerable — particularly to snap attacks, where a thief uses brute force to break the cylinder in two and then manipulate the cam inside. Anti-snap cylinders with TS007 3-star ratings exist precisely to prevent this, and we fit them as a matter of course when replacing a cylinder on any patio or French door.

French doors introduce an additional complexity: when two leaves meet in the middle, one leaf is typically held in place by flush bolts top and bottom, while the other contains the main multipoint lock. If the door drops on its hinges — common on uPVC frames after several years — the hooks and rollers no longer line up with the keeps in the frame, and the handle becomes very stiff or will not lift at all. Many Slough residents describe this as the door 'sticking' or the key 'not turning properly', when what has actually happened is that the alignment has drifted by just a few millimetres. Sometimes a hinge adjustment resolves it; other times the gearbox has been stressed to the point of failure and needs replacing.

Our mobile locksmiths arrive at your property carrying gearboxes, cylinders, handles and keeps suited to the most common uPVC door brands and profile sizes found across Slough — including doors installed in the SL1, SL2 and SL3 postcode districts. Because we work from a fully stocked van rather than a fixed shop, we can carry out the majority of patio and French door lock repairs on the same visit. A failed multipoint gearbox, for instance, can usually be measured, matched and swapped out within the hour, restoring all the locking points across the door simultaneously. Where a door requires a specific or less common part, we will source it quickly and return as soon as it arrives, often the same day. For upvc door lock repair Slough residents need, speed of service matters — a French door that will not lock properly overnight is a security risk, not an inconvenience to schedule around next week.

We approach every job with damage-free methods where possible. Forcing a uPVC door frame to access the mechanism, or drilling out a cylinder without first exploring a cleaner route, can warp the profile and compromise the weather seal — and uPVC frames are not cheap to replace. Our technicians use the correct removal tools and work methodically, keeping the frame and glazing intact. Where a French door knob lock or lever handle is seized, we diagnose whether the problem is in the handle assembly, the spindle, or the gearbox before removing anything, so the right part is replaced without unnecessary dismantling.

Not every patio or French door uses the same locking format, and correct identification matters. The majority of modern uPVC French doors rely on a multipoint gearbox operated by a euro cylinder, but some older or timber-framed French doors use a traditional mortise lock set into the edge of the door stile. A French door mortise lock — sometimes called a mortise lock for French doors — requires a cutout in the door edge and is engaged by a key rather than a handle-and-key combination. Where the two leaves meet on a rebated profile, a 5 lever rebated mortice lock for French doors is the appropriate choice: the rebated faceplate accounts for the overlap between the two door leaves, and the five-lever mechanism meets the minimum standard that most home insurance policies require. This is different from a standard French door mortise lock set used on flush-meeting doors, and fitting the wrong type will result in a lock that either does not engage correctly or creates a gap at the meeting point.

For uPVC patio sliders, the lock is usually a hook-bolt mechanism built into the door edge, operated by a key cylinder on the face of the door. These are generally not interchangeable with French door gearboxes, and the keeps in the frame need to align precisely with the hook position. When we carry out a door lock replacement Slough call-out for a patio slider, we measure the hook throw, the backset, and the cylinder length before sourcing a replacement, ensuring the new lock operates smoothly and engages fully. We also check that the keeps are secure in the frame — worn or loose keeps are a surprisingly common secondary cause of a lock that feels stiff or incomplete. If you are unsure how to lock French doors with lever handles on your existing installation, or whether your current lock arrangement actually secures both leaves effectively, our technicians can assess the whole door and advise on the most appropriate solution for your property.

A French door or patio slider that will not lock is an emergency regardless of the hour. Langley Locksmith operates as a 24 hour locksmith Slough service — our lines are answered through the night, at weekends, and on bank holidays, and we send a technician straight away. We are usually with you in about 30 minutes, though travel time varies depending on where in the Slough area you are located. If you are locked out of your property or the door has been damaged in a break-in and needs immediate securing, call 01753 251949 and one of our team will talk through the situation with you and confirm an exact price before anyone sets off. The factors that determine the final quote include the type of lock and door profile, any parts needed, the time of day, and the distance involved — everything is explained clearly on the phone. We also serve commercial clients. As a commercial door locksmith, we work with landlords, letting agents, housing associations, small businesses and office tenants across Slough who need patio or French door locks repaired or replaced quickly to keep properties secure and tenants safe. If you manage a block of flats or a commercial premises in the SL postcode area and have a door that is compromised, our insured technicians can attend at short notice and issue the documentation your records require. Call 01753 251949 — we answer 24/7.

Sometimes a lock has simply reached the end of its useful life, or the security profile needs updating rather than repairing. Lock change Slough call-outs for patio and French doors are common after a break-in attempt, after a tenancy change, or when an older multipoint system is no longer functioning reliably despite previous adjustments. In those cases, we replace the gearbox, cylinder, handles and keeps as a complete unit, ensuring that all the components are matched and that the new installation meets current security standards. We fit anti-snap euro cylinders as standard, and we can also advise on handle configurations — including how to lock French doors with lever handles if the existing setup has been changed or the handles replaced with a type that is not fully compatible with the gearbox. A proper lever-to-gearbox connection matters: if the spindle does not engage the gearbox fully when the handle is lifted, the multipoint hooks will not deploy, and the door will appear locked without actually being secured. This is a detail that gets missed when non-specialist trades replace handles on French doors, and it is something our technicians check specifically on every installation and after any handle replacement job.

When you contact Langley Locksmith about a patio slider or French door lock issue in Slough, we will ask you a few straightforward questions: what the door type and frame material are, what the lock is doing or not doing, whether the door is currently secure, and your address. This helps us confirm that we are bringing the right parts and can give you an accurate quote before we arrive. We do not use call centres or outsource our work — the technician who attends is trained, experienced, and insured, and they carry out the job themselves. Ownership verification is part of our standard process: we will ask you to confirm your connection to the property, particularly on rental addresses or commercial premises, before proceeding. For anyone in Slough who has a French door or patio slider that is not locking properly, dropping on its hinges, or failing to engage its multipoint mechanism, the right move is to call us before the problem becomes a full lockout or a security breach. We are available around the clock — call 01753 251949 and we will have someone with you as quickly as possible.